In Michigan, there is no law that allows a spouse to avoid testifying in a criminal proceeding where they are the alleged victim. If this spousal privilege existed, it would be difficult to prosecute domestic violence cases if the "victim" wanted to protect his/her spouse and tank the prosecution's case. This privilege does apply in other areas of the law, even criminal cases, but not when the other spouse is an alleged victim of the other spouse.
That being said, the prosecutor will subpoena witnesses for a trial in domestic violence, and the star witness will be that spouse victim. The "victim" may not want to testify, and have even asked the prosecutor to dismiss charges and they were told that is not going t happen. If subpoenaed, the spouse victim will be ordered to appear in court for the trial, failure to appear is contempt of court and the spouse victim could face major consequences.
The more important question is whether a prosecutor and judge are willing to consider enforcing that, and taking the steps to take the spouse into custody against their will - this is called a material witness warrant in Michigan. The law says the following:
When it appears to a court of record that a person is a material witness in a criminal case pending in a court in the county and that there is a danger of the loss of testimony of the witness unless the witness furnishes bail or is committed if he or she fails to furnish bail, the court shall require the witness to be brought before the court. After giving the witness an opportunity to be heard, if it appears that the witness is a material witness and that there is a danger of the loss of his or her testimony unless the witness furnishes bail or is committed, the court may require the witness to enter into a recognizance with a surety in an amount determined by the court for the appearance of the witness at an examination or trial. If the witness fails to recognize, he or she shall be committed to jail by the court, until he or she does recognize or is discharged by order of the court.
I've had judges threaten to issue this warrant in domestic violence cases where the victim either indicated they would not show, or did not appear after the subpoena was served. I've also had judges and prosecutor say frankly that they were not willing to go arrest and harass a "victim" of domestic violence, and if they did not show, then that was their choice, and the case would essentially be dismissed.
I've handled DV cases both as a prosecutor and as a defense lawyer all around the State of Michigan; I have a good idea on the courts that pursue these warrants and force victims into court, and the courts that will not pursue this. It makes all the difference when deciding whether or not to set a case for trial, or pursue a resolution with the prosecutor prior to trial.